Gantrez™ copolymers

Chemistry: Vinyl Ether polymers and copolymers

Gantrez™AN copolymers contain alternating units of methylvinylether and maleic anhydride. The fundamental character of this polymerization requires that a maleic anhydride unit must be adjacent to a methylvinylether unit and vice versa, resulting in a true alternating copolymer. Gantrez AN (anhydride form) is available in the molecular weight range of 130M-2500M. The polymers are white, hygroscopic powders soluble in tetrahydrofuran (THF) and M-Pyrol™ solvent; insoluble in aliphatic and halogenated hydrocarbons. All four grades have a glass transition temperature of 151-154°C, independent of molecular weight and form transparent, tack-free films.

Stabileze™ QM polymers are produced in a manner similar to that of Gantrez AN but with the added monomer decadiene present to yield a crosslinked, water-swellable resin. The polymer is a white, free-flowing powder with a glass transition temperature of approximately 150°C. The solid can be dispersed in water without coagulating, and the anhydride function will hydrolyze directly or through the action of base. A neutralized 0.5 percent solution in water at pH 7 and 25°C has a viscosity range of 45,000-70,000 cP.

Gantrez S95 and S97 have repeating co-maleic acid units produced by hydrolysis of Gantrez AN. The polycarboxylic acid derivatives with a pH of ~2 at 5 percent concentration are available either as viscous solutions or white powders. The vicinal dicarboxylic acid functionality of these materials is useful in a number of applications. The free acid forms are water-soluble, giving clear and tacky films. Solution rheology can be modified by the addition of salts and bases.

Gantrez MS-955 is a mixed salt of sodium/calcium and is supplied as a free-flowing powder. The copolymer is soluble in water and produces solutions with high viscosity.

Ethyl, isopropyl and n-butyl half esters are produced by opening up the anhydride in alcohol. These polymers, based on AN-119, are sold as 50 percent solutions in ethanol or isopropanol. They are water soluble when neutralized greater than 40 percent using either an organic or inorganic base. Adhesive strength can be adjusted through controlling the degree of neutralization. Films are flexible, clear and glossy and have improved water resistance compared to Gantrez S.